A few others are reporting this aswell. Virgil couldn't get on with Google Chrome. And another user has to use a VPN. I'll look into it now and speak with Virgil. It'll be fixed.
Please if you can post a screenshot of the error you get when connecting without a VPN/Proxy.
It's a temporary solution. I'd still work on making sure Firefox works. Reflush the DNS and delete cache again. Then turn your router on and off to change your IP (depends on your router but it works for most). Then try again on firefox. I don't want any browser being restricted on my forums.